A large number of service personnel is currently working in the computer field service industry. Field service engineers are, in their daily work routines, required to identify the exact part of malfunctioning computer equipment. But, at the present time, they are not fully equipped to do it in the most efficient and reliable way.
For example, when identifying video interface problems such as a blank screen of a computer monitor, missing colors or unsynchronized picture, a technician must decide which part of computer is defective--a video card or the monitor. The most common way is to check the monitor by replacing it with a properly functioning one from a nearby work station. However, this is a time consuming and cumbersome operation which causes downtime for the other system. In addition a compatible monitor is not always immediately available for the test. This is especially true when diagnosing the cause of failure of the LCD display of a single laptop computer owned by an individual computer operator.
In such cases, the technician should use an oscilloscope, but such device is not readily available either, because it cannot usually be part of the field engineer's repair kit because of its weight, dimensions and cost. As a result, the technician is usually forced to make a guess based on his previous experience, and is frequently wrong, resulting in wasted time, high cost of repair and a dissatisfied customer.
The same approach is normally taken by technicians when diagnosing problems in audio equipment by replacing audio cards, audio cables, loudspeakers and microphones in multimedia computer systems. The same wrong conclusion could be made if the spare units are not available at the time of test.
Various signal testers are widely known and most of them are related to the telephone and communication systems. However, no portable, simple, cheap and universal device which could be used for identifying defective parts of video/audio interfaces of any computer system is available.
For example, U.S. Pat. No. 4,837,488 issued Jan. 6, 1989 to Donahue teaches a portable identifier and tester unit which identifies corresponding computer cable ends. However, this tester is limited in application only to the evaluation of the continuity of the cable lines and does not have the capability of testing the video/audio computer interfaces.
Another type of tester is taught by U.S. Pat. No. 4,843,620 issued Jan. 27, 1989 to Hagedorn. The patent describes a hand-held telephone line signaling tester for signal measuring in telephone lines. The device is dedicated to test specific telephone systems, has a complex design with a key pad and LCD display and cannot be used for computer interface testing.
In addition, other testers and apparatus relate mostly to telephone systems and there is no prior art of the video/audio tester device for use in computer interface testing.